<template>
  <div class="list">
    <header v-show="isShow">
      <div class="returns">
        <i class="iconfont icon-fanhui"></i>
      </div>
      <div class="search">
        <i class="iconfont icon-fangdajing"></i>
        <span>搜索商品名称</span>
      </div>
      <div class="go-home">
        <img src="@/assets/images/home.png" alt="" />
      </div>
    </header>
    <section>
      <div class="list-l" ref="left">
        <ul class="l-item">
          <li
            v-for="(item, index) in leftData"
            :key="index"
            :class="{ active: index == currentIndex }"
            @click="goScroll(index)"
          >
            {{ item.name }}
          </li>
        </ul>
      </div>

      <div class="list-r" ref="right">
        <div>
          <ul v-for="(item, index) in rightData" :key="index" class="shop-list">
            <li v-for="(k, i) in item" :key="i">
              <h2>{{ k.name }}</h2>
              <ul class="r-content">
                <li v-for="(j, idx) in k.list" :key="idx">
                  <img :src="j.imgUrl" alt="" />
                  <span>{{ j.name }}</span>
                </li>
              </ul>
            </li>
          </ul>
        </div>
      </div>
    </section>
    <Tabbar></Tabbar>
  </div>
</template>

<script>
import BetterScroll from 'better-scroll'
import Tabbar from '@/components/common/Tabbar.vue'
import http from '@/common/api/request.js'
export default {
  name: "List",
  data() {
    return {
      isShow: true,
      leftData: [],//左侧数据
      rightData: [],//右侧数据
      rightBScroll: '',//右侧滑动BScroll
      allHeight: [],//承载右侧每一块的高度值
      scrollY: ''//右侧滚动距离
    }
  },
  computed: {
    currentIndex() {
      return this.allHeight.findIndex((item, index) => {
        return this.scrollY >= item && this.scrollY < this.allHeight[index + 1]
      })
    }
  },
  components: {
    Tabbar
  },
  async created() {
    let res = await http.$axios({
      url: '/api/goods/list'
    })
    let leftArr = [];
    let rightArr = [];
    res.forEach(v => {
      leftArr.push({
        id: v.id,
        name: v.name
      })
      rightArr.push(v.data);
    })
    this.leftData = leftArr;
    this.rightData = rightArr;

    this.$nextTick(() => {
      //左侧滑动
      new BetterScroll(this.$refs.left, {
        click: true,
        bounce: false
      });
      //右侧滑动
      this.rightBScroll = new BetterScroll(this.$refs.right, {
        click: true,
        probeType: 3,
        bounce: false
      });
      //统计右侧所有板块高度值，并且放入数组中
      let height = 0;
      this.allHeight.push(height);
      //获取右侧每一块高度
      let uls = this.$refs.right.getElementsByClassName('shop-list');
      //把dom对象转换成功真正的数组
      Array.from(uls).forEach(v => {
        height += v.clientHeight
        this.allHeight.push(height)
      })
      //得到右侧滚动的值
      this.rightBScroll.on('scroll', (pos) => {
        this.scrollY = Math.abs(pos.y);
        if(Math.abs(pos.y) >= 50) {
          this.isShow = false;
        }else {
          this.isShow = true;
        }
      })
    })
  },
  methods: {
    goScroll(index) {
      this.rightBScroll.scrollTo(0, -this.allHeight[index], 300);
    }
  }

}
</script>

<style scoped lang='less'>
.list {
  display: flex;
  flex-direction: column;
  width: 100vw;
  height: 100vh;
  overflow: hidden;
}
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 1.173333rem;
  background-color: #7cda50;
  .returns {
    line-height: 1.173333rem;
    padding: 0 0.233333rem;
    i {
      color: #fff;
      font-size: 0.75rem;
    }
  }
  .search {
    display: flex;
    align-items: center;
    flex: 1;
    padding: 0.1rem 0.266666rem;
    background-color: #ffffff;
    border-radius: 1rem;
    i {
      padding-right: 0.16rem;
      color: #666;
      font-size: 0.48rem;
    }
    span {
      color: #666;
      font-size: 0.45rem;
    }
  }
  .go-home {
    padding: 0 0.266666rem;
    line-height: 0.3rem;
    img {
      width: 0.8rem;
      height: 0.8rem;
    }
  }
}
section {
  display: flex;
  flex: 1;
  overflow: hidden;
}
.list-l {
  width: 2.48rem;
  background-color: #fff;
  border-right: 1px solid #cccccc;
  overflow: hidden;
  .l-item {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    li {
      width: 100%;
      padding: 0.08rem 0;
      margin: 0.5rem 0;
      text-align: center;
      font-size: 0.373333rem;
      &.active {
        color: #b54f4a;
        border-left: 6px solid #b54f4a;
      }
    }
  }
}
.list-r {
  flex: 1;
  overflow: hidden;
  .shop-list {
    text-align: center;
    h2 {
      padding: 0.4rem 0;
      font-size: 0.5rem;
      font-weight: 400;
    }
    .r-content {
      display: flex;
      flex-wrap: wrap;
      li {
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        width: 33.33%;
        padding: 0.266666rem 0;
        img {
          width: 1.413333rem;
          height: 1.413333rem;
        }
        span {
          font-size: 0.426666rem;
        }
      }
    }
  }
}
::v-deep.tabbar {
  border-top: 1px solid #cccccc;
}
</style>